JPH0491297A - Production of safety protective paper - Google Patents

Abstract

PURPOSE:To obtain the subject paper for producing bank bills, etc., requiring prevention of forgery by passing a strip, etc., through the tip groove of a protruding part in each guide, provided on a wire and having an uneven part, sinking the guide in a paper stock suspension, then dehydrating the suspension and providing a window with movement of the guide in forming a paper layer. CONSTITUTION:A belt mechanism having each guide 2' composed of an uneven part and a groove 3 at the tip of a protruding part thereof is installed on a wire part 4 keeping a prescribed interval and rotated by a rotating and driving pulley 7 and an undriven pulley 8 to pass a strip or yarn 1 through the groove 3 at the tip of the protruding part in the guide 2'. The strip or yarn 1 is then sunk in a paper stock suspension 5 and water in the paper stock suspension 5 is dehydrated from the wire 4 to the lower part (c). The guide' 2 composed of the uneven part is moved upward at a place (d) where a paper layer (P) is mostly formed. Thereby, the objective paper having window parts 6 in the absence of the paper stock on parts in contact with the tips of the protruding parts in an intact state in which the strip or yarn 1 is inserted into the paper layer (P) is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing security paper for the production of products that require counterfeit prevention, such as banknotes, securities, admission tickets, etc. It is related to.

[Conventional technology]

It is well known in the prior art to insert protective strips or threads of plastic film into banknotes. Particularly, those having windows where there is no stock on part of the strip or thread, as currently seen on pound notes, are extremely effective in preventing counterfeiting. The method for manufacturing a product having this window portion is described in specification EP 00590 filed in Europe and the United States by Portals Ltd. in the UK.
No. 56 and TJ S P 4462866 (Method for manufacturing paper with windows in which security devices exist). This is manufactured using a so-called cylinder paper machine, in which a cylindrical wire mesh (cylinder mold) with a partially textured surface rotates in a vat containing a stock suspension. The strip or thread rotates together while contacting the irregularities of the processed surface. As a result, the portion of the strip or yarn that was in contact with the protrusion on the surface of the wire mesh becomes a window on which no stock is present.

[Problem that the invention seeks to solve]

Until now, the protective film consisted of plastic film).
As a method for manufacturing paper having a window portion where no paper stock is present on a part of the IJ knob or thread, the above-mentioned specification EP 005,9056 of Portals Ltd. of England and US Pat.
Due to its mechanism, the circular mesh papermaking method described in P 4462866 has a relatively low papermaking speed, and since the wire mesh is processed into an uneven shape to form the windows, the outline of the windows is not sharp. The paper thickness on both sides (width direction) of the window was also slightly thinner than other parts, which had the disadvantage that those parts appeared brighter when viewed under transmitted light.

The present invention addresses these issues.

Measures for solving problem C] A belt mechanism is installed on the wire portion, which has a guide consisting of a concave and convex portion, and has a groove at the tip of the convex portion.
Pass the J-tube or thread through the groove at the tip of the convex part of the guide and immerse it in the stock suspension. When the water in the paper stock suspension has been drained downward from the wire and the paper layer is almost formed, the uneven mechanism is moved upward, leaving the strip or thread inserted in the paper layer. This is a method for producing safety paper in which a window portion in which no paper stock is present is formed on a portion of the paper (the part that was in contact with the tip of the convex portion) according to the shape of the groove at the tip of the convex portion.

[Effect]

A strip or thread is passed through a groove at the tip of a convex portion of a guide having concave and convex portions placed on the wire, and the guide is immersed in the stock suspension. When the moisture in the stock suspension is dehydrated downward from the wire and a paper layer is formed, if the guide with the uneven part is moved upward, the strip or thread will be inserted into the paper layer. Since there is no stock on the strip or thread portion that was in contact with the groove at the tip of the convex portion, a window appears on the surface of the paper.

〔Example〕

Next, the method for manufacturing the safety paper of the present invention will be specifically explained with reference to the drawings.

Embodiment 1 FIG. 1 is a partial schematic diagram showing an embodiment of the present invention. 1st
In the figure, (1) is a strip or thread, and (
2) is a guide having uneven parts for immersing them in the stock suspension, and (4) is a wire (mesh surface) for dehydrating the paper stock suspension to form the paper layer tp+. . Second
The figure is a side view of figure 1 and shows a strip or thread (1
) is the groove (3) at the tip of the convex part of the guide (2) which has a concave and convex part.
passed through. Figure 3 shows the stock suspension (5) of Figure 1.
The water in the stock suspension (5) is drained from the wire downward fa). When the guide (2) is pulled upward when the paper layer +Pl is almost formed, the IJ knob or thread (1) will be inserted into the paper layer iPl, but it will not touch the groove of the guide (2). Since there is no paper stock on the part where the paper was used, a window (61) is formed where the strip knob or thread (1) appears on the surface of the paper layer (Pl), as shown in FIG.

Example 2 Fig. 5 shows a case where the wire (4) is moving like in a Fourdrinier paper machine, and Fig. 6 is a side view thereof. Installed a device consisting of a ring-shaped guide '+2' with rotating uneven parts, a drive motor (9) and a boo IJ-+71 which is rotated by Noyafuto 001, and a non-driven pulley (8). do. S) The IJ tube or yarn (1) is passed through the groove (3) at the tip of the convex portion of the guide (ri) and is embedded in the stock 1 suspension (5). Stock suspension (5
) is dehydrated downward to +C+ and the strip or thread (
1) separates from the guide (ri), but the part of the IJ knob or thread (1) that was in contact with the groove (3) at the tip of the convex part of the guide (c) remains in the paper stock suspension (5). There is no direct liquefaction, and once the paper layer tPl is formed, the paper stock has no fluidity, so a new paper layer +Pl is not formed on top of it, and as a result, there are no fibers in that part. It is formed as a window (6). Note that the distance between the guide protrusions (
The interval between the windows can be adjusted by adjusting the pitch (pitch), and the groove at the tip of the convex part can be adjusted, for example, as shown in Figure 7 (A side view, B bottom view) and Figure 8 (A゛ side view, B bottom view). By changing the shape, it is possible to freely change the shape of the window portion (6) formed as shown in FIGS. 9 and 10.

〔effect〕

As shown in the examples, the present invention makes it possible to produce paper having windows on which no stock is present on a strip or part of the yarn, and in particular, it is also possible to produce it using a Fourdrinier paper machine, As a result, the papermaking speed can be increased compared to conventional circular mesh papermaking, and further counterfeit prevention effects can be achieved by combining various perforations by the Fourdrinier paper machine with the above-mentioned windows. Further, the window portion can be formed into any desired shape by changing the shape of the tip of the IJ knob or thread holding convex portion, and its outline can be made clear.

[Brief explanation of drawings]

Fig. 1 is a partial schematic diagram of a safety paper manufacturing apparatus according to the present invention, Fig. 2 is a side view of Fig. 1, and Fig. 3 is a state in which the apparatus shown in Fig. 1 is immersed in a stock suspension. Figure 4 is a diagram showing a state in which a window is formed, Figure 5 is a front view of a safety paper manufacturing device when the wire is moving like in a fourdrinier machine, The figure is a side view of figure 5, the 7th country is a side view when the shape of the groove at the tip of the convex part of the guide is triangular, and the figure 7 tB+ is the bottom view of the 7th country is the convex part of the guide. A side view when the shape of the groove at the tip is diamond-shaped, and Figure 8 +B+ is a bottom view of the 8th country. Figure 9 is a diagram of the state of the window when the sheet is made using the guide in Figure 7. FIG. 10 is a diagram showing the state of the window portion when a sheet is produced using the guide shown in FIG. 8. (1) Strip or thread (2) Insertion guide (3) Groove at the tip of the protrusion

Claims (1)

[Claims] A belt mechanism having a guide consisting of concave and convex portions and a groove at the tip of the convex portion is installed on a wire portion that maintains a constant interval, and a strip or thread is passed through the groove at the tip of the convex portion of the belt to suspend the paper stock. The strip or thread is immersed in the suspension, and when the water in the paper stock suspension is drained downward from the wire and the paper layer is almost formed, the guide consisting of the uneven part is moved upward to remove the strip or thread from the wire into the paper layer. 1. A method for producing safety paper, characterized in that the paper has a window portion where no stock is present on the portion that was in contact with the tip of the convex portion while the paper is inserted into the paper.